Study on acoustic properties of hydrate-bearing sediments with reconstructed CO2 hydrate in different layers during CH4 hydrate mining.

Natural gas hydrate (NGH), a clean energy source with huge reserves in nature, and its safe and efficient exploitation fits perfectly with the UN Sustainable Development Goals (SDG-7). However, large-scale NGH decomposition frequently results in subsea landslides, reservoir subsidence, and collapse. In this work, in order to achieve safe and efficient exploitation of NGHs, the stability variation of different reservoir layers by depressurization/intermittent CO2/N2 injection (80:20 mol%, 50:50 mol%) was investigated using acoustic properties (P-wave velocity, elastic modulus), as well as reservoir subsidence under an overburden stress of 10 MPa. The P-wave velocity increased from 1282 m/s to 2778 m/s in the above-reservoir and from 1266 m/s to 2564 m/s in the below-reservoir, significantly increasing reservoir strength after CO2 hydrate formation. The P-wave velocity and elastic modulus in the top reconstructed reservoir were continually decreased by the shear damage of the overlying stress, while they remained stable in the bottom reconstructed reservoir during hydrate mining. However, due to superior pressure-bearing ability of the top CO2 hydrate reservoir, which was lacking in the bottom CO2 hydrate reservoir, the reservoir subsidence was relieved greatly. Despite the stiffness strength of reconstructed reservoir was ensured with CO2/N2 sweeping, the skeletal structure of CH4 hydrate reservoir was destroyed, and only the formation of CO2 hydrate could guarantee the stability of P-wave velocity and elastic modulus which was most beneficial to relieve reservoir subsidence. A large amount of CO2 was used in reservoir reconstruction and CH4 hydrate mining, which achieved the geological storage of CO2 (SDG-13). This work provided a new idea for safe and efficient NGHs mining in the future, and the application of acoustic properties served as a guide for the efficient construction of reconstructed reservoirs and offers credible technical assistance for safe exploitation of NGHs.

The prevalence of azoospermia factor microdeletion on the Y chromosome of Chinese infertile men detected by multi-analyte suspension array technology.

AIM: To develop a high-throughput multiplex, fast and simple assay to scan azoospermia factor (AZF) region microdeletions on the Y chromosome and establish the prevalence of Y chromosomal microdeletions in Chinese infertile males with azoospermia or oligozoospermia. METHODS: In total, 178 infertile patients with azoospermia (non-obstructed), 134 infertile patients with oligozoospermia as well as 40 fertile man controls were included in the present study. The samples were screened for AZF microdeletion using optimized multi-analyte suspension array (MASA) technology. RESULTS: Of the 312 patients, 36 (11.5%) were found to have deletions in the AZF region. The microdeletion frequency was 14% (25/178) in the azoospermia group and 8.2% (11/134) in the oligospermia group. Among 36 patients with microdeletions, 19 had deletions in the AZFc region, seven had deletions in AZFa and six had deletions in AZFb. In addition, four patients had both AZFb and AZFc deletions. No deletion in the AZF region was found in the 40 fertile controls. CONCLUSION: There is a high prevalence of Y chromosomal microdeletions in Chinese infertile males with azoospermia or oligozoospermia. The MASA technology, which has been established in the present study, provides a sensitive and high-throughput method for detecting the deletion of the Y chromosome. And the results suggest that genetic screening should be advised to infertile men before starting assisted reproductive treatments.

[Detecting human chromosome anomalies with primed in situ labeling (PRINS)].

Numerical chromosome anomaly was one of the most important kinds of human chromosome diseases by inducing pregnancy loss, miscarriage, infant death, congenital malformations and nerve damage. The present study was to establish a rapid, reliable and reasonable multicolor primed in situ labeling (PRINS) protocol for diagnosing numerical anomaly in human chromosome. First, nuclei of cultured lymphocytes and sperms were labeled with the method of PRINS, and then nuclei of cultured lymphocytes, sperms and other specimen were labeled with the method of updated non-ddNTP-blocking multicolor PRINS technique. The labeling effect of different target sequences and the feature of different fluorochromes were evaluated by experiment. Meanwhile, several parameters of PRINS were optimized to obtain more homogeneous and stable labeling effect. At last, the applicative value of PRINS was evaluated by comparing the clinical effect and labeling characteristics between FISH probe and PRINS. In the present study, several chromosomes were simultaneously marked successfully in the same sperm nucleus within 2.5 hours. And the frequency of one-color-labeling reached 99%. The many advantages, compared with FISH, make PRINS become the first choice in diagnosing diseases related to numerical anomaly in human chromosome.